1. Field of the Invention
The present invention relates to inertial lock mechanisms, and, more particularly, to a mechanism which normally permits free relative movement between two adjacent objects but which prevents relative movement when a predetermined relative acceleration occurs.
2. Description of the Prior Art
In recent years, inertial lock mechanisms have become increasingly common, typically as safety devices in vehicles. Such mechanisms, for example, assist in anchoring seat belt straps by means of inertial reels which lock in the event of a collision of the vehicle. Generally, these inertial locks utilize centrifugal forces generated during rapid rotation of the inertial reels to engage a friction or latch means which is not engaged when the inertial reels are more slowly rotated. These devices are best suited to applications having relatively high rotational speeds, such as automobile seat belt spools which spin when the seat belt straps are pulled from the spools.
One of the most significant dangers present in the passenger compartment of a vehicle during a crash is the forward folding of the seat backs. Because seat backs in many automobiles must fold forwardly to permit access to an area behind the seats, such seat backs are now usually equipped with lock mechanisms. Generally, these mechanisms are merely simple latches with manual levers for disengaging the latches so as to permit forward folding of the seats when access is desired. Folding of the seat backs equipped with such lock mechanisms is inconvenient, particularly due to the usual positioning of the latch release levers near the seat back hinges or on the rearward side of the seat backs.
Inertial lock mechanisms have not been utilized in conjunction with forwardly folding vehicle seat backs due to the absence of the high rotational speeds required for inertial reel operation. Accordingly, it is an object of the present invention to provide an inertial lock mechanism suitable for use with forwardly folding vehicle seat backs. It is a further object of the present invention to provide an inertial lock mechanism which is adaptable to a wide variety of applications and which is not dependent upon high rotational speeds such as those required for inertial reel use.